usb: dwc2: invalidate the dcache before starting the DMA

We should invalidate the dcache before starting the DMA. In case there are
any dirty lines from the DMA buffer in the cache, subsequent cache-line
replacements may corrupt the buffer in memory while the DMA is still going on.
Cache-line replacement can happen if the CPU tries to bring some other memory
locations into the cache while the DMA is going on.

Signed-off-by: Eddie Cai <eddie.cai.linux@gmail.com>
Reviewed-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>

diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c
index ae7d8fb1da7153d4994b08f31deaa051f91a5eea..0e5df15a0de0420393a35f1f1f3236c8a1024549 100644 (file)
--- a/drivers/usb/host/dwc2.c
+++ b/drivers/usb/host/dwc2.c
@@ -817,12 +817,19 @@ static int transfer_chunk(struct dwc2_hc_regs *hc_regs, void *aligned_buffer,
               (*pid << DWC2_HCTSIZ_PID_OFFSET),
               &hc_regs->hctsiz);
 
-       if (!in && xfer_len) {
-               memcpy(aligned_buffer, buffer, xfer_len);
-
-               flush_dcache_range((unsigned long)aligned_buffer,
-                                  (unsigned long)aligned_buffer +
-                                  roundup(xfer_len, ARCH_DMA_MINALIGN));
+       if (xfer_len) {
+               if (in) {
+                       invalidate_dcache_range(
+                                       (uintptr_t)aligned_buffer,
+                                       (uintptr_t)aligned_buffer +
+                                       roundup(xfer_len, ARCH_DMA_MINALIGN));
+               } else {
+                       memcpy(aligned_buffer, buffer, xfer_len);
+                       flush_dcache_range(
+                                       (uintptr_t)aligned_buffer,
+                                       (uintptr_t)aligned_buffer +
+                                       roundup(xfer_len, ARCH_DMA_MINALIGN));
+               }
        }
 
        writel(phys_to_bus((unsigned long)aligned_buffer), &hc_regs->hcdma);